Engineering Commons^™

Energy Efficient Loop Unrolling For Low-Cost Fpgas, Naveen Kumar Dumpala

Masters Theses

Many embedded applications implement block ciphers and sorting and searching algorithms which use multiple loop iterations for computation. These applications often demand low power operation. The power consumption of designs varies with the implementation choices made by designers. The sequential implementation of loop operations consumes minimal area, but latency and clock power are high. Alternatively, loop unrolling causes high glitch power. In this work, we propose a low area overhead approach for unrolling loop iterations that exhibits reduced glitch power. A latch based glitch filter is introduced that reduces the propagation of glitches from one iteration to next. We explore …

Navigation Instruction Validation Tool And Indoor Wayfinding Training System For People With Disabilities, Linlin Ding

Masters Theses

According to World Health Survey, there are 785 million (15.6%) people in the world that live with a disability. It is a well-known fact that lack of access to public transportation is a barrier for people with disabilities in seeking work or accessing health care. In this research, we seek to increase access to public transportation by introducing a virtual pre-travel training system that enables people with disabilities to get familiar with a public transportation venue prior to arriving at the venue. Using this system, users establish a mental map of the target environment prior to their arrival to the …

Evaluation Of Impedance Control On A Powered Hip Exoskeleton, Punith Condoor

Masters Theses

This thesis presents an impedance control strategy for a novel powered hip exoskeleton designed to provide partial assistance and leverage the dynamics of human gait. The control strategy is based on impedance control and provides the user assistance as needed which is determined by the user’s interaction with the exoskeleton. A series elastic element is used to drive the exoskeleton and measures the interaction torque between the user and the device. The device operates in two modes. Free mode is a low impedance state that attempts to provide no assistance. Assist mode increases the gains of the controller to provide …

Efficient Scaling Of A Web Proxy Cluster, Hao Zhang

Masters Theses

With the continuing growth in network traffic and increasing diversity in web content, web caching, together with various network functions (NFs), has been introduced to enhance security, optimize network performance, and save expenses. In a large enterprise network with more than tens of thousands of users, a single proxy server is not enough to handle a large number of requests and turns to group processing. When multiple web cache proxies are working as a cluster, they talk with each other and share cached objects by using internet cache protocol (ICP). This leads to poor scalability.

This thesis describes the development …

Query On Knowledge Graphs With Hierarchical Relationships, Kaihua Liu

Masters Theses

The dramatic popularity of graph database has resulted in a growing interest in graph queries. Two major topics are included in graph queries. One is based on structural relationship to find meaningful results, such as subgraph pattern match and shortest-path query. The other one focuses on semantic-based query to find question answering from knowledge bases. However, most of these queries take knowledge graphs as flat forms and use only normal relationship to mine these graphs, which may lead to mistakes in the query results. In this thesis, we find hierarchical relationship in the knowledge on their semantic relations and make …

Magneto-Electric Approximate Computational Framework For Bayesian Inference, Sourabh Kulkarni

Masters Theses

Probabilistic graphical models like Bayesian Networks (BNs) are powerful artificial-intelligence formalisms, with similarities to cognition and higher order reasoning in the human brain. These models have been, to great success, applied to several challenging real-world applications. Use of these formalisms to a greater set of applications is impeded by the limitations of the currently used software-based implementations. New emerging-technology based circuit paradigms which leverage physical equivalence, i.e., operating directly on probabilities vs. introducing layers of abstraction, promise orders of magnitude increase in performance and efficiency of BN implementations, enabling networks with millions of random variables. While majority of applications with …

Bmi, Tumor Lesion And Probability Of Femur Fracture: A Probabilistic Biomechanics Approach, Zhi Gao

Masters Theses

found that most of these factors are directly or indirectly linked to subjects’ BMI (body mass index). Thus, from a statistical perspective, BMI could be an overall indicator of the probability of femur fracture from a sideways fall. Using a biomechanics approach coupled with statistical data we investigate this relationship with a large cohort of postmenopausal women aged 50-79 from WHI-OS (Women’s Health Initiative Observational Cohort). The cohort is divided into six sub-cohorts by BMI where each fall-related factor is examined and compared with each other. Significant differences are discovered among cohorts in terms of femur size, aBMD (areal bone …

Skynet: Memristor-Based 3d Ic For Artificial Neural Networks, Sachin Bhat

Masters Theses

Hardware implementations of artificial neural networks (ANNs) have become feasible due to the advent of persistent 2-terminal devices such as memristor, phase change memory, MTJs, etc. Hybrid memristor crossbar/CMOS systems have been studied extensively and demonstrated experimentally. In these circuits, memristors located at each cross point in a crossbar are, however, stacked on top of CMOS circuits using back end of line processing (BOEL), limiting scaling. Each neuron’s functionality is spread across layers of CMOS and memristor crossbar and thus cannot support the required connectivity to implement large-scale multi-layered ANNs.

This work proposes a new fine-grained 3D integrated circuit technology …

Oracle Guided Incremental Sat Solving To Reverse Engineer Camouflaged Circuits, Xiangyu Zhang

Masters Theses

This study comprises two tasks. The first is to implement gate-level circuit camouflage techniques. The second is to implement the Oracle-guided incremental de-camouflage algorithm and apply it to the camouflaged designs.

The circuit camouflage algorithms are implemented in Python, and the Oracle- guided incremental de-camouflage algorithm is implemented in C++. During this study, I evaluate the Oracle-guided de-camouflage tool (Solver, in short) performance by de-obfuscating the ISCAS-85 combinational benchmarks, which are camouflaged by the camouflage algorithms. The results show that Solver is able to efficiently de-obfuscate the ISCAS-85 benchmarks regardless of camouflaging style, and is able to do so 10.5x …

Electroless Deposition & Electroplating Of Nickel On Chromium-Nickel Carbide Powder, Jeffrey Rigali

Masters Theses

Engineered components can gain desirable properties when coated with surface materials. Wear-resistant coatings can improve the performance of contacting surfaces and allow for an extended life of the parts. Hard chromium has been the plating material of choice for certain wear and corrosion- resistant coatings because of its desirable combination of chemical resistance, adhesion, and mechanical properties. However, hexavalent chromium, a component of the process for applying hard chromium coatings, has been recognized by the EPA as having hazardous health and environmental impacts. Existing and planned environmental regulations restricts the use of process chemicals containing hexavalent chromium ions. This substantiates …

Improving The Efficiency Of Wind Farm Turbines Using External Airfoils, Shujaut Bader

Masters Theses

Wind turbine efficiency typically focuses on the shape, orientation, or stiffness of the turbine blades. In this thesis, the focus is instead on using static fixed airfoils in proximity to the wind turbine to control the airflow coming out of the turbine. These control devices have three beneficial effects. (1) They gather air from “higher up” where the air is moving faster on average (and therefore has more kinetic energy in it). (2) They throw the used (and slowed down air) downwards. This means that any turbines in the wind farm behind the lead turbines do not get “stale” air. …

Supporting Trajectory Udf Queries And Indexes On Postgis, Pyoung Woo Yang, Kwang Woo Nam

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

In this paper, we propose a system model for querying and indexing the GPS trajectory of moving objects on PostGIS/PostgreSQL. We developed moving object data types including MPoint(moving point), MDouble(moving double) for GPS trajectories. Also, various moving objects UDFs(user-defined functions) are implemented for moving objects queries. For efficient query processing, r-tree index is extended for trajectory, and pre-materialization techniques are proposed for fast UDF processing. Experimental results show that the pre-materialization techniques are about 1.2 times faster than naïve query processing using r-tree index.

Gis Investigation Of Crime Prediction With An Operationalized Tweet Corpus, Anthony J. Corso, Abdulkareem Alsudais

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

Social media as the de facto communication channel is being used to disseminate one’s diurnal self-revelations. This profound discovery often contains double-talk, peculiar insights, or contextual information about real-world events. Natural language processing is regularly used to uncover both obvious and latent knowledge claims within disclosures published amid the complex environment. For example, a perpetrator with first-hand knowledge of their criminal incident uses social media to post critical information about it. A geographic information system (GIS) is capable of large-scale point data analysis and possesses methods that enable dataset processing, evaluation, and automatic spatial visualization. Such an artifact—fused with traditional …

Qkan - Management Of Drainage System Data With Qgis, Jörg Höttges

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

Based on QGIS a database structure and a set of plugins have been developed to improve the workflow for the hydraulic design of urban drainage systems for consulting engineers. The main goal is pre- and postprocessing in combination with various commercial hydraulic simulation software packages. The plugins provide import and export functionalities, simulation result viewing and generation of longitudinal cross sections in a CAD program. All modules make intensive use of SQL based spatial functions instead of functions implemented in QGIS, because of their stability, higher flexibility and speed due to the indexing functionality. On the other hand the database …

Analyzing The Performance Of Nosql Vs. Sql Databases For Spatial And Aggregate Queries, Sarthak Agarwal, Ks Rajan

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

Relational databases have been around for a long time and spatial databases have exploited this feature for close to two decades. The recent past has seen the development of NoSQL non-relational databases, which are now being adopted for spatial object storage and handling, too. While SQL databases face scalability and agility challenges and fail to take the advantage of the cheap memory and processing power available these days, NoSQL databases can handle the rise in the data storage and frequency at which it is accessed and processed - which are essential features needed in geospatial scenarios, which do not deal …

Performance Of Adhesive And Cementitious Anchorage Systems, Mirna Mendoza

Masters Theses

Post-installed anchoring systems are used extensively in Massachusetts Department of Transportation (MassDOT) projects due their ease of attachment to existing structures. However, recommendations on materials from various manufacturers are currently lacking for certain situations such as long-term tension loading. The purpose of the investigation presented in this thesis was to provide guidance on the use of anchoring systems to MassDOT. This research project evaluated the behavior of adhesive and cementitious bonded anchoring systems per the Stress-versus-Time-to-Failure approach found in the provisional standard AASHTO TP-84 in order to provide recommendations pertaining to the test method. Supplemental short-term anchor pullout tests were …

Incorporating Seasonal Wind Resource And Electricity Price Data Into Wind Farm Micrositing, Timothy A. Pfeiffer

Masters Theses

Currently, most micrositing techniques aim to maximize annual energy production (AEP) or minimize cost of energy (COE) with no direct regard to revenue. This research study developed a method that utilizes the seasonal electricity price and wind data to microsite wind farms in terms of profitability. To accomplish this, six candidate wind farms with differing layouts and spacing were selected at a given location. They were then simulated using a wake modeling software to produce expected power outputs at different wind speeds, wind directions, and turbulence intensities. By interpolating the power output tables with wind data, a power time-series was …

Virtualization Of Closed-Loop Sensor Networks, Priyanka Dattatri Kedalagudde

Masters Theses

The existing closed-loop sensor networks are based on architectures that are designed and implemented for one specific application and require dedicated sensing and computational resources. This prevents the sharing of these networks. In this work, we propose an architecture of virtualization to allow sharing of closed-loop sensor networks. We also propose a scheduling approach that will manage requests from competing applications and evaluate their impact on system utilization against utilization achieved by more traditional, dedicated sensor networks. These algorithms are evaluated through trace-driven simulations, where the trace data is taken from CASA’s closed-loop weather radar sensor network. Results from this …

A Magnetic Resonance Compatible Knee Extension Ergometer, Youssef Jaber

Masters Theses

The product of this thesis aims to enable the study of the biochemical and physical dynamics of the lower limbs at high levels of muscle tension and fast contraction speeds. This is accomplished in part by a magnetic resonance (MR) compatible ergometer designed to apply a load as a torque of up to 420 Nm acting against knee extension at speeds as high as 4.7 rad/s. The system can also be adapted to apply the load as a force of up to 1200 N acting against full leg extension. The ergometer is designed to enable the use of magnetic resonance …

Experimental Study On Viscoelastic Fluid-Structure Interactions, Anita Anup Dey

Masters Theses

It is well known that when a flexible or flexibly-mounted structure is placed perpendicular to the flow of a Newtonian fluid, it can oscillate due to the shedding of separated vortices at high Reynolds numbers. If the same flexible object is placed in non-Newtonian flows, however, the structure's response is still unknown. The main objective of this thesis is to introduce a new field of viscoelastic fluid-structure interactions by showing that the elastic instabilities that occur in the flow of viscoelastic fluids can drive the motion of a flexible structure placed in its path. Unlike Newtonian fluids, the flow of …

Development Of High Early-Strength Concrete For Accelerated Bridge Construction Closure Pour Connections, Stephanie Castine

Masters Theses

Accelerated bridge construction (ABC) has become a popular alternative to using traditional construction techniques in new bridge construction and existing bridge deck replacement because of the reduction of time spent in field activities. A key feature of bridges built using ABC techniques is the extensive use of prefabricated components. Prefabricated components are joined in the field using small volume closure pours involving high performance materials (steel and concrete) to ensure adequate transfer of forces between components. To date, the materials developed for closure pours have been based on proprietary components, so a need has arisen for development of mixes that …

Evaluating Variances Between Departments Of Transportation In New England To Create A Strategic Transportation Workforce, Chelsea Bouchard

Masters Theses

As the baby boomer generation approaches retirement, the transportation workforce is increasingly under strain. Employees are exiting the industry in larger volumes than incoming hires; which is creating a need to reevaluate and revamp work processes. In addition, the industry is transitioning into the 21st century and that is requiring the adaptation of new technologies. The gap between old and new employee skills is growing and seen throughout the industry. There is a growing need and opportunity to develop a new set of job competencies which create job specifications and job postings, which support the organization’s strategic plan. In this …

Evaluation Of New England Bridges For Bat Roosting Including Methodology And Case Studies, Angela Berthaume

Masters Theses

Bats are known and documented to use bridge structures as roosts in various locations throughout the United States and abroad, but there is limited knowledge of how bats use bridges in New England. Significant population declines due to White-Nose Syndrome have resulted in several bat species being listed as state or federally threatened or endangered. If bats are using bridges as roosts, significant effort is required to ensure they are not disturbed or harmed during construction or maintenance work, requiring knowledge of assessment methods to identify likely roost locations in bridges. This thesis describes a two summer study evaluating the …

Cross Case Study Of An Elementary Engineering Task, John Heffernan

Doctoral Dissertations

Designerly play has been identified as a fundamental component of childhood learning (Baynes, 1994; Petroski, 2003). However, as students enter grade one and beyond, the increasing academic focus has resulted in the loss of opportunities for designerly play (Zhao, 2012). At the same time, there are increasing calls to increase the number, skill, and diversity of STEM workers (Brophy, Portsmore, Klein, & Rogers, 2008). The robotics based Elementary Engineering Curriculum (Heffernan, 2013) - used by students in this study - and other similar projects have the potential to increase the STEM pipeline but elementary engineering is not well-understood. Research is …

An Evaluation Of Traffic Control Devices And Driver Distraction On Driver Behavior At Railway-Highway Grade Crossings, Radhameris A. Gomez Gabriel

Doctoral Dissertations

At-grade crossings (grade crossings) are those crossings in which any part of a roadway intersects with railroad tracks. Safety at these railroad-highway grade crossings is a major concern, with traffic control warning devices serving as the main mechanisms for improving safety. There are three factors that influence a driver’s behavior at a given crossing. First, traffic control devices, including warning devices at the railroad-highway grade crossings, provide the driver with information whose impact will depend in part on the likelihood that the driver knows whether to glance in the direction of the device based on prior experience, and in part …

Synthesis, Characterization And Application Of Block Copolymer And Nanoparticle Composites, Yue Gai

Doctoral Dissertations

The “bottom-up” fabrication of functional hybrid material can be achieved by using directed self-assembly of functional nanoparticles (NP) and block copolymers (BCP) as templates. The versatile nanostructures of BCP provide possibilities to precisely control NPs spatial distribution and the resulting hybrid materials exhibit enhanced electrical, mechanical and optical functionalities. Three main topics related to BCP/NP composites are discussed in this dissertation: I) the spatial distribution of large NP in linear BCP; II) the morphology control of BCP templates with new architectures; and III) the magneto-optical properties of hybrid material using magnetic NPs. For well-ordered BCP/NP composite, the ratio of NP …

Modeling And Modifying Day-To-Day Travel Behaviors: Empirical Results And Methodological Advances, Yue Tang

Doctoral Dissertations

The increasing availability of individual-level longitudinal data provides the opportunity to better understand travelers'\ day-to-day learning process of their choice alternatives, which enables potentially more accurate predictions of choice patterns in a network with uncertainties. In this thesis, an instance-based learning (IBL) model for travel choice is developed within route-choice context, where on each day a traveler's decision depends on her entire choice history in the past. Learning in this model is based on the power law of forgetting and practice, which is shown to be capable of capturing various psychological effects embedded in travelers'\ day-to-day learning process, including the …

Covert Wireless Communications In A Dynamic Environment, Tamara V. Sobers

Doctoral Dissertations

This dissertation investigates covert communication in dynamic wireless communication environments. A key goal is to provide insight about the capabilities of a transmitter desiring to remain covert and analogously, the capabilities of the party attempting to detect covert communications. The first chapter provides background on covert communications prior to this work. The second chapter studies the theoretical limits of covert communication and proves that positive rate is achievable when a jammer is added to the classical Alice/Bob/Warden Willie model. The third chapter expands on the second chapter by considering more generally the impact of the dynamics of the environment on …

Belief-Space Planning For Resourceful Manipulation And Mobility, Dirk Ruiken

Doctoral Dissertations

Robots are increasingly expected to work in partially observable and unstructured environments. They need to select actions that exploit perceptual and motor resourcefulness to manage uncertainty based on the demands of the task and environment. The research in this dissertation makes two primary contributions. First, it develops a new concept in resourceful robot platforms called the UMass uBot and introduces the sixth and seventh in the uBot series. uBot-6 introduces multiple postural configurations that enable different modes of mobility and manipulation to meet the needs of a wide variety of tasks and environmental constraints. uBot-7 extends this with the use …

Characterization Of Electronic And Ionic Transport In Soft And Hard Functional Materials, Lawrence A. Renna

Doctoral Dissertations

Control over concurrent transport of multiple carrier types is desired in both soft and hard materials. For both types of materials, I demonstrate ways to characterize and execute governance over both electronic and ionic transport, and apply these concepts in the fabrication of devices with applications in conducting composites, photovoltaics, electrochemical energy storage, and memristors. In soft materials, such as polymers, the topology of the binary polymer mesoscale morphology has major implications on the charge/ion transport. Traditional approaches to co-continuous structures involve either using blends of polymers or diblock copolymers. In polymer blends, the structures are kinetically trapped and …